Upon printing (copying) a plurality of pages, a trial print (trial copy) function which trial-prints some pages prior to main print processing and starts print processing after it is confirmed if the user wants to start, cancel, change, or the like the main print processing is known (see Japanese Patent Laid-Open No. 2003-208298). In terms of the nature of the trial print function, the printing operation of a job to be processed by this function is paused when the user confirms the trial print result or changes the job after confirmation.
Upon printing a secure document, a secure print function which requires authentication to output and allows to output at an arbitrary timing so as to prevent information from leaking to a third party when print processing starts at a position beyond eyeshot is known (see Japanese Patent Laid-Open No. 2001-341361).
The two functions, i.e., the trial print and secure print functions are independent functions, and have no relevance to each other. A job (secure job) which requires authentication to output, and a job (non-secure job) which does not require any authentication to output have a feature in that although they require different control processes before the beginning of execution, their control processes have no difference after their print processes start in practice. For this reason, upon executing the trial print processing of a secure job, when the owner of that secure job leaves from an image forming apparatus main body for the purpose of replenishing paper sheets for the main print processing, toner, or the like after the job is interrupted, a third party may manipulate the secure job which has undergone the trial print processing and waits for post-processing. Hence, the main print operation of the secure job may be executed, and the document security may not be protected.